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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in mammalian cells
Remarks:
Type of genotoxicity: gene mutation
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP-compliant guideline study, available as unpublished report, no restrictions, fully adequate for assessment.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2011
Report Date:
2011

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)
GLP compliance:
yes (incl. certificate)
Type of assay:
mammalian cell gene mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Remarks:
migrated information: powder
Details on test material:
- Name of test material (as cited in study report): Potassium tetrafluoroborate
- Physical state: white crystalline powder, odourless
- Analytical purity: 99.1%
- Lot/batch No.: BWF10626
- Expiration date of the lot/batch: 31 July 2013
- Storage condition of test material: Ambient temperature

Method

Target gene:
Thymidine kinase (TK) locus on chromosome 11.
Species / strain
Species / strain / cell type:
mouse lymphoma L5178Y cells
Metabolic activation:
with and without
Metabolic activation system:
Aroclor 1254 induced rat liver S9-mix
Test concentrations with justification for top dose:
0.62, 1.2, 2.5, 4.9, 7.0, 10 mmol/L
Vehicle / solvent:
- Solvent used: DMSO
Controlsopen allclose all
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
methylmethanesulfonate
Remarks:
without S9 mix
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
3-methylcholanthrene
Remarks:
with S9 mix
Details on test system and experimental conditions:
METHOD OF APPLICATION: in medium

DURATION
- Exposure duration: 24 hours in the absence of S9-mix, 4 hours in the presence of S9-mix.

NUMBER OF REPLICATIONS:
Duplicate cultures were used for each concentration of the test substance.

GROWTH RATE AND VIABILITY:
On the day of exposure, the growth rate and viability of the cells were checked: the growth rate was 12.3 hours (doubling time), the viability was 96% (expressed as trypan blue exclusion).

DETERMINATION OF CYTOTOXICITY
The cytotoxicity of the test substance was determined by measuring the relative initial cell yield, the relative suspension growth (RSG) and the relative total growth (RTG).
Evaluation criteria:
A response was considered to be positive if the induced mutant frequency (mutant frequency of the test substance minus that of the vehicle negative control) was more than 126 mutants per 1,000,000 clonable cells.

A response was considered to be equivocal if the induced mutant frequency was more than 88 mutants (but smaller than 126 mutants) per 1,000,000 clonable cells. Any apparent increase in mutant frequency at concentrations of the test substance causing more than 90% cytotoxicity and with no evidence of mutagenicity at RTG > 10%, was considered to be an artefact and not indicative of genotoxicity.

The test substance was considered to be mutagenic in the gene mutation test at the TK-locus if a concentration-related increase in mutant frequency was observed, or if a reproducible positive response for at least one of the test substance concentrations was observed.

The test substance was considered not to be mutagenic in the gene mutation test at the TK-locus if it produced neither a dose-related increase in the mutant frequency nor a reproducible positive response at any of the test substance concentrations.
Statistics:
No statistical analysis was performed.

Results and discussion

Test results
Species / strain:
mouse lymphoma L5178Y cells
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
in the absence of S9-mix the test substance was slightly toxic to the cells
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
RESULTS OF CYTOTOXICITY TEST:
In the absence of S9-mix the test substance was slightly toxic to the cells, resulting in a decrease of 24% in relative total growth (RTG). In the presence of S9-mix no toxicity was observed.

CONTROLS:
The negative controls were within historical background ranges and treatment with the positive control yielded the expected significant increase in mutant frequency compared to the negative controls.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

The test substance is considered to be non-mutagenic in this gene mutataion assay.
Executive summary:

In a GLP compliant gene mutation test performed according to OECD guideline 476, potassium tetrafluoroborate was examined for its potential to induce gene mutations at the TK-locus of cultured mouse lymphoma L5178Y cells, in both the absence and the presence of a metabolic activation system (S9-mix). One test was conducted. In this test 6 duplicate cultures were treated for 24 hours and 4 hours in the absence and presence of S9-mix, respectively. The test substance was dissolved in dimethylsuphoxide (DMSO). The highest concentration tested and evaluated for mutagenicity was 10 mmol/L. The test substance was slightly toxic to the cells in the absence of S9 -mix. A slight decrease by 24% of the relative growth (RTG) was observed at the highest dose of 10 mmol/L. In the presence of S9 -mix no cytotoxicity was observed. In both the absence and presence of S9-mix no increase in mutant frequency was observed at any test substance concentration evaluated. All data were within the range of the negative control and the historical background. Methyl methanesulphonate (MMS) and 3-methylcholanthrene (MCA) were used as positive control substances in the absence and presence of the S9-mix, respectively; DMSO served as negative control. The negative controls were within historical background ranges and treatment with the positive control yielded the expected significant increase in mutant frequency compared to the negative controls. It is concluded that under the conditions used in this study, the test substance potassium tetrafluoroborate is not mutagenic at the TK-locus of mouse lymphoma L5178Y cells in both the absence and presence of metabolic activation (S9-mix).